最近在使用 Visual Studio 进行 c++ 程序的书写时发现了有部分细节需要手动进行改变，能够提高做题或者从其他地方复制代码进行运行的效率，在这里做部分总结

1.Visual Studio 没有自带万能头(bits/stdc++.h),需要自己配置

  • 首先需要找到头文件所在文件夹，这里可以随便先创建一个项目，以 iostream 为例：

  • 然后按住 CTRL 鼠标左键点击 iostream ,进入后左键点击 iostream 选择打开所在的文件夹:

  • 这时就进入了 Visual Studio 存放头文件的目录下，在此目录下新建一个名为 bits 的文件夹，在文件夹中新建一个头文件名为 stdc++.h，文件内容如下：
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// C++ includes used for precompiling -*- C++ -*-

// Copyright (C) 2003-2017 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file stdc++.h
 *  This is an implementation file for a precompiled header.
 */

 // 17.4.1.2 Headers

 // C
#ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdalign>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif

// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

#if __cplusplus >= 201103L
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif

保存并退出，现在就可以正常使用万能头了

2.Visual Studio 认为 scanf 函数不安全，必须使用 scanf_s 替换，否则报错

  • 找到 Visual Studio 安装目录，打开名为 VC 的文件夹，点击 VCProjectItems 进入后可以找到一份名为 newc++file.cpp 的文件：

    所有新建的.c / .cpp文件都会拷贝到newc++file.cpp这个文件中，接下来在里面加入一段宏定义:

    1
    #define_CRT_SECURE_NO_WARNINGS 1

保存并退出，现在使用 scanf 就不会报错了